1. Field of the Invention
The present invention relates generally to an intraocular lens for implanting within the lens capsule of an eye following the removal of the biological contents of the lens capsule. The present invention further relates to apparatus and the method of implanting the novel lens in the lens capsule of an eye.
2. State of the Art
Cataract is a common ailment effecting the human eyes, especially the eyes of older people. Cataract is in fact the most common cause of blindness. Removal of the clouded biological lens material of the affected eye will restore light perception, but full rehabilitation requires that the refractive power of the natural lens be replaced by some other means
In the somewhat distant past, the replacement of the refractive power of the natural lens was achieved by the use of spectacles and contact lenses. However, both spectacles and contact lenses have limitations. Spectacles produce major optical distortions, and patients, especially older people, have a difficult time adjusting to the various problems involved in wearing and caring for contact lenses.
Current state of the art practice in cataract surgery includes the implanting of an artificial lens in the eye to mimic the function of the original, natural lens. The artificial lenses are referred to as intraocular lenses, and more than 900,000 are implanted in the United States each year. The most common procedure involves the placement of a rigid plastic lens in the eye of the patient following the removal of the natural, biological lens material.
There are problems associated with the use of rigid plastic lenses. The hard plastics used can erode into delicate ocular tissues, leading to medical complications. The accommodative, or focusing capability of the eye is completely lost inasmuch as normal accommodation is effected by deformation of the biological lens. Rigid plastic lenses can not deform and therefor have no provision for accommodation. Further, the rigid plastic lenses require that a relatively large incision be made for their insertion into the eye. This results in extended post-operative recovery times and increased risk of induced corneal astigmatism when compared with surgery involving smaller incisions.
There has been developed a surgical procedure called phacoemusification which allows the biological lens material to be removed through a relatively small incision of as little as 3 millimeters in comparison to incisions in the range of 7 to 11 millimeters that are required for the insertion of a rigid plastic lens into the eye. Other surgical procedures to remove lens material through small incisions are presently being developed. It has been proposed to make the replacement lens from a compressible material which can be inserted into the eye through the smaller incision.
In U.S. Pat. No. 4,619,662 an intraocular lens is disclosed which consists of a preformed, molded mantle having substantially thick side walls of a preformed shape and size. It is taught that the preformed sidewalls contain at least 30% of the volume of the lens. The preformed, molded lens has a single cannula extending therefrom. In use, the air is evacuated from the interior of the preformed mantle through the cannula to collapse the mantle for insertion into the eye through the incision in the eye. The lens of U.S. Pat. No. 4,619,662 is designed to be positioned in the posterior or anterior chamber of the eye. There is no suggestion of positioning the lens within the lens capsule of the eye.
The collapsed, molded mantle of U.S. Pat. No. 4,619,662 is inserted into the eye using the cannula, and once the mantle is within the eye, additional polymer material is then injected into the lens through the cannula to fill the void volume of the molded mantle. Once the lens is filled, the cannula is incised from the lens. There are no means provided for flushing the lens to remove small air bubbles attached to the interior surface of the molded mantle following the filling of the void volume with the polymeric material. In fact, there is no recognition of such a problem with residual air bubbles, and there is no suggestion, of course, as to a means of eliminating the residual air bubbles.
3. Objectives
A principal objective of the invention is to provide a surgeon with a novel intraocular lens system, with means and method of implanting the lens within the lens capsule of an eye.
A particular objective of the invention is to provide such a lens system wherein the lens comprises a very thin-walled skin forming a substantially enclosed, collapsible sac such that the lens skin can be folded into a small size which can be inserted into the lens capsule of an eye through a small incision being no larger than 3 or 4 millimeters, and further wherein a pair of longitudinal, flexible tubes extend from the lens skin, with the lumen of each tube communicating with the inside of the sac formed by the lens skin and with the tubes being adapted to extend from the eye through the incision following the insertion of the collapsed, folded, thin walled sac into the lens capsule of the eye.
An additional objective of the present invention is to provide means and a method for inflating the sac formed by the lens skin after the folded lens skin has been placed within the lens capsule of the eye and for removing residual air bubbles from the inflated sac, wherein a liquid is injected through one of the tubes extending from the sac to inflate the sac, with additional fluid then being flushed through the sac and out the other one of the tubes extending from the sac to expel air bubbles from the sac.
Another objective of the present invention is to provide such a novel intraocular lens system in which the liquid used to fill the lens skin within the lens capsule of the eye is adapted to form a clear, resilient elastomer, wherein the artificial lens formed by the skin and the filling closely mimics both the dimensions and the compliance of a natural, biological lens, so that the ciliary apparatus of the eye is able to deform the artificial lens in the same manner it does a natural, biological lens to provide accommodation with the artificial lens.